The purpose of this trial is to investigate the effectiveness of the CREON2000A for improving asthma control and preventing or reducing asthma events in children with mild to moderate allergic asthma. The patented CREON2000A device is being developed as an environmental control intervention that will serve as an adjunctive treatment of asthma. The compact energy efficient design allows the use of the device in 95% of homes built after 1994, and in 74% of all US homes. Based on this statistics, the CREON2000A intervention, if efficacious, could benefit the majority of children with asthma in the United States. The promising results of our preliminary SBIR Phase I study warrant further investigation of this device in a larger clinical trial. This clinical trial is designed asa Phase II, multicenter, twelve month, double blind, randomized, sham controlled, parallel group study. It compares improvement in asthma control, as measured by the Asthma Control Questionnaire, in mild to moderate allergic persistent asthmatic children living in homes with a CREON2000A Irradiation system to those living in homes with sham units. Secondary endpoints of this trial are: morning peak expiratory flow rates, a reduction of total number of inhalation of rescue medications, asthma exacerbations, and missed days from school or work. The trial includes an exploratory objective designed to investigate whether CREON2000A's mechanism of action is related to protein structural changes by UV irradiation leading to the decreased allergenicity of indoor allergens. An interdisciplinary team of experienced, university and small business based researchers, with the necessary technical and clinical expertise has been assembled to investigate this potentially important asthma control intervention. The current approach for the management of asthma is very costly. In 2006, 8 billion dollars was spent treating childhood asthma. The annual cost per child for implementing multifaceted environmental control interventions, as recommended by the national asthma guidelines, ranges between $750 to $1,000 which is comparable to the annual cost of asthma medications. The necessity to modify behavior of parents, so they will maintain time-consuming and often expensive interventions, creates a significant barrier for adhering to these recommendations. The CREON2000A device requires minimal maintenance (i.e., changing bulb and small filter once a year) and, because it is simple to use, home occupants do not have to change their daily routines. For that reason, the acceptability and patient adherence with this intervention is excellent. The projected annual cost of this intervention including the amortization of the CREON2000A unit over 10 years is $244. Therefore, the application of this device and technology could optimize the medical management of asthma leading to a significant reduction in the costs associated with treating this chronic disease.